Blame!: Fort of Silicon Creatures

In a future version of Earth, there is a city grown so chaotically massive that its inhabitants no longer recall what “land” is. Within this megastructure the silent, stoic Killy is on a mission to find the Net Terminal Gene—a genetic mutation that once allowed humans to access the cybernetic NetSphere. Armed with a powerful Graviton Beam Emitter, Killy fends off waves of attacks from fellow humans, cyborgs and silicon-based lifeforms. Along the way, he encounters a highly-skilled scientist whose body has deteriorated from a lengthy imprisonment who promises to help Killy find the Net Terminal Gene, once she settles a score for herself… (Source: Kodansha USA) *Note: Includes one extra chapter.*

Steel and rust. The City structure has endlessly propagated itself for so many years that the reason for such growth has long since been forgotten. Even within such a techo-dystopia, humans still exist: The Electrofishers. Driven to the brink of extinction, they are visited by a traveller—a man named Killy. But will his presence bring the Electrofishers ruination or hope … ? (Source: Kodansha USA)